The lens epithelial and fiber cell membrane is of great importance in maintaining the integrity of the normal lens. Alterations in this structure lead to loss of clarity, with a dramatic reduction in vision. The protein content and quality of the lens membrane is known to be critical for proper functioning of the lens, and it has been often demonstrated that alterations of the lens membrane proteins occur with aging and cataractogenesis. Therefore, it is important to understand the nature of lens membrane proteins and their integration within the fiber cell membrane. We intend to carry out a basic biochemical and structural characterization of lens plasma membrane proteins. Using classical extraction techniques and electrophoretic methods, lens intrinsic and extrinsic membrane proteins will be isolated and primary NH- terminal amino acid sequence information will be obtained. This limited sequence data will be used to construct antibody and oligonucleotide probes for further investigation of lens membrane proteins through immunochemical and cDNA cloning techniques. The proteolysis of certain membrane proteins will be investigated using COOH-terminal amino acid sequencing of the protein and its "degradation" products in order to determine the exact cleavage site, which will help to define the type of enzyme(s) which are acting to cleave membrane proteins, possibly leading to cataract.